12 comments:

Cowboy---->HumanThis statement is widely beleived to be true. Inductively, anyway. However:Human---->CowboyThe vast majority of humans can easily be demonstrated to not be cowboys. This statement is false, soHuman<---->Cowboyis also false. Therefore using the substitution property is inappropriate and the proof is invalid.Oh, snap!

That's doesn't work. You're assumptions are:that Humans existed at the same time as mammoths,that Indians existed at the same time as MammothsIndians and Cowboys are both human, and Cowboys existed at the same time as Indians

Or in other words,Mammoths-->HumansMammoths-->IndiansCowboys-->HumansIndians-->HumansCowboys-->Indians

So given the present existence of Humans, we can conclude nothing. Given the present existence of Mammoths, we can conclude only Humans and Indians. Given the present existence of Indians, we can conclude only Humans. Given the present existence of Cowboys, we can also conclude only Indians. None of these satisfy Cowboys^Indians, therefore the statement is false given your assumptions.

I would also argue that cowboy-->human is false, with my evidence being toy story.

Here is another proof:

Statements1. Cowboys did not exist at the same time as cowboysReasons:1. HISTORY

but your proof is right there: Its a cowboy riding a mammoth. And obciously, this prooves that there were cameras around at the same time as mammoths, and cowboys were around before cameras, so this makes it especially true.